Short answers, pulled from the story.
Predeterminism is the philosophy that all events of history, past, present, and future, have already been decided or are already known by God, fate, or some other force, including human actions. Unlike simple causal determinism, predeterminism implies that a conscious being deliberately fixed those events in advance. The term is closely related to, but frequently confused with, determinism, predestination, and fatalism.
Determinism usually refers to a naturalistically explainable causality of events, while predeterminism implies a person or conscious being who planned or controlled that causality before events occurred. Predeterminism, by definition, requires at least a passive but all-knowing observer, if not an active designer. Some philosophers in free-will debates argue that predeterminism back to the origin of the universe is simply what they mean by the more common term determinism.
R. E. Hobart was the pseudonym of Dickinson S. Miller, a student of William James and for some years a colleague in the Harvard philosophy department. In 1934 he published an article in Mind entitled Free Will as Involving Determination and Inconceivable Without It, now considered one of the definitive statements of determinism and compatibilism. Hobart argued that humans have the power to choose among alternatives, and he explicitly endorsed the existence of alternative possibilities that can depend on absolute chance.
In a 1957 article in The Philosophical Review, Philippa Foot argued that the ordinary language meaning of saying actions are determined by motives does not carry the same weight as strict physical determinism. She cited Bertrand Russell's definition of causal determinism and doubted that everyday claims about motivation implied it. She also criticized the idea that free will requires indeterminism, questioning whether a person could be held responsible for chance actions chosen for no particular reason.
Predestination is a specific theological doctrine, most famous in Calvinist Christian theology, asserting that a supremely powerful being has fixed all events and outcomes in the universe in advance. Predeterminism, when pushed to its logical conclusion, leads to the same idea: a conscious being who is omnipotent, omniscient, and presumably supernatural must determine all actions in advance. Because predestination already names that concept, some philosophers consider predeterminism redundant or unclear by comparison.
The term predeterminism is frequently used in the context of biology and heredity, representing a form of biological determinism. A fetus's future physical and emotional characteristics, traced through a chain of events stretching back before birth, might be called predetermined by heredity. However, the word predetermined implies a conscious being doing the determining, such as a genetic scientist examining genomes; without that observer, the characteristics are simply determined by heredity, not predeterminated.